Genetica

Biology 202
Fall 2006
Exam 1

MATCHING: Match the definition with the correct term. 2 pts

1. __D__ A term applied to an gene that produces a range of phenotypes in individuals of the same genotype

2. __G__ Allele interaction in which the heterozygote displays a phenotype that is a blend of phenotypes produced by each allele

3. __J__ Type of reproduction in which two parentsdonate genetic material to offspring

4. __L__ Term that describes the failure of chromosomes to separate during cell division

5. __A__ A type of chromosomes that does not carry genes conferring sexual characteristics

6. __S__ Phase of meiosis in which crossing-over occurs

7. __F__ Term that describes chromosomes that carry the same type of genes

8. __C__ Describes an individual thathas two copies of every chromosome in most cells

9. __H__ An allele that is expressed in either the homozygous or heterozygous condition

10. _I___ Term used to describe a gene that has multiple phenotypic effects on an individual

|a. Autosome |h. Dominant |o. Asexual reproduction |
|b. Co-dominance|i. Pleiotropic |p. Sex-linked |
|c. Diploid |j. Sexual reproduction |q. Recessive |
|d. Expressivity |k. Penetrance |r. Sex Chromosome |
|e. Haploid|l. Non-disjunction |s. Prophase I |
|f. Homologous chromosomes |m. Prophase II | |
|g. Incomplete dominance |n. Sister chromatids | |

MULTIPLECHOICE: Choose the best answer from the answers provided. There is only one best answer for each question. 2 pts

1. In corn, a food-storing part of the seed known as the endosperm may be starchy or waxy. The allele for starchy endosperm, W, is dominant to the allele for waxy endosperm, w. A starch and a waxy plant are mated, resulting in 425 starchy plants and 409 waxy plants. What must bethe genotypes of the two parent plants?
a. Ww X Ww
b. Ww X ww
c. ww X WW
d. ww X ww

2. In humans, nearsightedness and the disorder PKU are both inherited as recessive autosomal traits. Two phenotypically normal people have a child that is nearsighted and has PKU. What proportion of their progeny are expected to be carriers (heterozygous) for each trait?
a. 1/4
b. 1/2
c. 3/4
d. 1/163. A daughter of the couple described above is nearsighted and heterozygous for the PKU enzyme. Her husband has the normal phenotypes for both traits, although his father was nearsighted and his mother had PKU. What is the probability that a child of this couple is nearsighted and has PKU?
a. 1/4
b. 1/2
c. 3/16
d. 1/8

4. Which of Mendel’s two laws describes the fact that a motheronly gives one allele for every gene to her offspring?
a. Law of Segregation
b. Law of Independent Assortment

5. If an individual is heterozygous at three gene loci, how many unique types of gametes can be made by that individual?
a. 2
b. 4
c. 8
d. none of the above

6. A male always inherits his Y chromosome
a. from his mother’s father.
b. from his mother’s mother.
c. from hisfather’s mother.
d. from his father’s father

7. Marfan Syndrome is an autosomal dominant disorder caused by a single gene mutation. Individuals with Marfan Syndrome experience a range of phenotypic effects including, but not limited to: disproportionately long arms, legs, fingers and toes; arched roof of the mouth; dislocation of the eye lens; weakened aorta; leaky heart valves; increased...